Patent attributes
A normally open hydraulic control valve includes: a linear solenoid unit; a spool driven by an output force of the linear solenoid unit to move forward; a valve body in which the spool is fitted; and a return spring for biasing the spool in a retreating direction. The valve body includes: a reaction force oil chamber for introducing hydraulic pressure, which presses the spool in a direction against a biasing force of the return spring, from the output port; and a damper oil chamber which suppresses vibration of the spool. The damper oil chamber is adjacent to the reaction force oil chamber with the third land portion of the spool therebetween. A slide gap which leaks and supplies oil from the reaction force oil chamber to the damper oil chamber is provided between the third land portion and the valve body. Thus, it is possible to quickly supply the oil to the damper oil chamber at the early stage of the operation without restriction on the arrangement, and to prevent delay in operation of the damper oil chamber.
